Medical devices may contain drugs either to improve the tolerance, efficacy or in vivo life-time of the device or the device serves as carrier for the drug. In any case the dose density (e.g. mg drug/mg device or mg drug/mm2 device surface), chemical stability, adherence, release rate, and total amount released are important and frequently critical features of the drug formulation. These properties are the more critical the more the requirements during production and application of the device vary or may even be contradictory. Drug-coated angioplasty catheters are typical examples: the drug coating must adhere firmly to tolerate mechanical stress during production including folding of balloons, crimping of stents, packaging, transportation to customers, and during final application, which involves passage through a narrow hemostatic valve, an introductory sheath or guiding catheter and a variable distance through possibly tortuous and narrow blood vessels. When the balloon is inflated the drug should be released within a minute or less as rapidly and as completely as possible. The problem was demonstrated by Cremers et al. (Cremers B, Biedermann M, Mahnkopf D, Bohm M, Scheller B. Comparison of two different paclitaxel-coated balloon catheters in the porcine coronary restenosis model. Clin Res Cardiol 2009; 98:325-330) who retrieved as much as 50% of the dose from balloons after expansion for one minute in coronary arteries of pigs, whereas other catheters coated with the same drug and dose but in a different formulation released more than 95%. Almost perfect results (i.e., loss of only 10% of dose and residual drug on the balloon after expansion in an artery of about 10%) were achieved with a rigid prototype balloon (Scheller B, Speck U, Abramjuk C, Bernhardt U, Bohm M, Nickenig G. Paclitaxel balloon coating—a novel method for prevention and therapy of restenosis. Circulation 2004; 110: 810-814). The application of the same coating composition to more flexible modern balloon catheters resulted in problems, i.e., larger premature loss of the drug. All types of balloon catheters display specific challenges in respect of coating the drug on the balloon, sufficient adherence or fast and complete release.